This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Diabetic retinopathy (DR) is the leading cause of blindness in the working age population. Unfortunately, no medical intervention is available to prevent or arrest diabetic retinopathy. The retinal lesions of DR include microaneurysms, vascular leakage and hemorrhage, macular edema and neovascularization, which lately will lead to great vision impairment. Histological lesions, such as basement membrane (BM) thickening, pericyte loss and acellular capillaries accompany the clinical lesions that develop, at least in part, due to hyperglycemia. The search for a better understanding of the pathogenesis of DR has relied heavily on animal models of the complications albeit mostly in the rat model. The use of primate models of DR would offer a distinct role in the development and assessment of novel treatments because of its close phylogenetic relationship with the human and similar eye structure and function. The common marmoset (Callithrix jacchus) is a new world monkey that has been used in the search for new treatments for other diseases. Marmosets weigh less than adult rats yet have eyes that are nearly twice the size of the rat eye. More importantly, our preliminary data indicates that the marmoset retina has a central macula, an important anatomical similarity compared to the human retina but absent in the rat retinas.